In this photo provided by Lauren Boushey, hundreds of college-age revelers crowd a street late Saturday, Oct. 12, 2013, in Bellingham, Wash., as police try to disperse the crowd. Multiple partiers were arrested during a melee late Saturday and early Sunday in Bellingham, according to police Sgt. Mike Scanlon. (AP Photo/Lauren Boushey)

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Bellingham police are stepping up party patrols and trying to track down on suspects after a riot of 500 people erupted near Western Washington University last weekend.

Bellingham police have arrested a fourth suspect in connection with the off-campus riot, the latest arrest was a Western Washington University student.

Police say Cameron S. Ehrlich, 19, who lives on campus, was booked into the Whatcom County Jail for investigation of riot, failure to disperse, and interfering with a street sign. Three non-students were arrested earlier in the week.

Police squad cars were damaged, street signs were knocked down and people threw beer cans and other items at officers during a large party that turned into a riot Saturday.

University spokesman Paul Cocke says Western continues to work closely with Bellingham police as they investigate.

Police Detective Gina Crosswhite says two other people have been identified but have not been located. The department has posted photos of 11 people it believes were involved in the melee on its website and it's asking the public to help identify them.